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F. H. LAPORGE 8? H'. J. BARKER.

SCOTCH YoKE FOR STEAM ENGINES. N0.-453,427. Patented June 2,1891.

UNITED STATES PATENT OFFICE.

FREDERICK H. LAFORGE, OF WVATERBURY, CONNECTICUT, AND HUGH J. BARKER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNORS TO THE LAFORGE ENGINE COMPANY, OF JERSEY CITY, NEIV JERSEY.

SCOTCH YOKE' FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 453,427, dated June 2, 1891. Application filed October 6, 1890. Serial No. 367,175. (No model.)

To all whom it may concern.-

Be it known that we, FREDERICK H. LA- FORGE, of WVaterbury, county of New Haven, State of Connecticut, and HUGH J. BAR- KER, of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented new Improvements in Scotch Yokes for Steam-Engines; and we do hereby declare the following, when taken in-connection with accompanying drawings and the letters of reference marked thereon, to be a full, clear, and exact description of the same, and which said drawings constitute part of this specification, and represent, in-

Figure 1, a sectional side view of the yoke and crank-block, showing a portion of the two piston-rods on line m, Fig. 2; Fig. 2, a face view of one of the guides of the yoke, showing the block in the groove.

This invention relates to an improvement in that class of steam-engines in which a pair of cylinders are arranged in line with each other, the two pistons connected between the cylinders by a yoke forming a guide in which a crank-block operates, so that a reciprocating movement imparted to the pistons will, through the said block, convert said reciprocating movement of the pistons into a rotary movement of the crank, and is an improvement upon the steam-engine for which Letters Patent No. 398,164 were granted to us Feb ruary 19, 1889. In that invention the guide which carries the crank-block is in the form of two parallel bars arranged at right angles to the direction of reciprocation of the pis tons, and between which guides the crank-. block slides under the rotary movement of the crank and so that the reciprocating movement of the pistons operating through said yoke will convert the reciprocating movement of the pistons into the rotary movement of the crank. The pistons also receive an oscillatory movement'whereby the pistons themselves operate as the valves for the admission and exhaust of steam. This oscillatory movement is imparted by means of a cam-shaped slot in the face of the guides or yoke in which a stud on the crank-block works and so that as the crank-block reciprocates from oneend of the guides to the other the said pin operating in the crank-slot imparts the requisite rocking or oscillatory movement to the yoke, and consequently to the pistons. The engine is designed to run with great rapidity, and wear to some extent between the cam-grooves and the stud working therein is unavoidable. Such wear permits a corresponding play between the stud and sides of the groove, which play will produce a rattling in the working of the engine.

The object of our present invention is to overcome this difficulty and make the engine, so far as the oscillatory movement of the yoke is concerned, noiseless; and the invention consists in the arrangement of an elastic block around the stud in the said can1- grooves, which block is adapted to expand to take up any wear or looseness which may occur between the sides of the grooves and the stud.

In illustrating the invention we represent only so much of the engine as is necessary to a clear understanding.

A represents one piston, and B the other, it being understood that they are arranged in substantially axial line with each other. The connection between the two pistons is formed by the yoke, composed of one guide C, attached to the piston A, andacorresponding guide D, attached to the piston B, the two guides being parallel and the plane of their faces being at right angles to the path of reciprocation. They are connected at their two ends by studs E, so as to hold them in their proper relation to each other. Between the two guides C D the crank-block F is arranged, and in which block the crank-pin G works, and so that as the yoke reciprocates under the'operation of the piston the crank will be caused to revolve, the crank-block sliding between the two guides. In the face of the guides is a cam-shaped groove H, (see Fig. 2,) into which a stud I projects from the crank-block, this stud traversing the groove as the block moves between the guides. The crank-block and stud, always following a straight line because of being held in a corresponding plane by the crank-pin, will impart an oscillating movement to the yoke corresponding to the said cam-shaped groove.

To give a considerable extent of bearing between the stud and the side of the groove, the stud is of less diameter than the width of the groove, and a block is introduced upon the stud, the said block being of a width corresponding to the width of the groove, and so that while the stud will rotate freely in the block the block will slide in the groove. Instead of making this block solid or making the stud of a diameter to take a bearing upon both sides of the groove, we construct the block in two parts a b. In the face of one block, as b, a seat is made for the stud I, and upon the other block, as a, a spring (Z is arranged, curved so as to form a seat for the opposite side of the stud I, as shown, this spring having a tendency to force the one part a of the block from the other part by its bearing upon the stud I, and'consequently holds the parts a b asunder with a yielding force, the power of the spring being sufiicient to press the two parts against their respective sides ofthe groove H, and yet bear firmly upon the stud I. Consequently any wear which may occur between the stud and the b ock, or between the block and the sides of the groove, will be taken up by the spring d, and theparts thus held firmly against the stud and against the corresponding sides of the groove prevent any possible play or rattle in the groove, yet perfect freedom is permitted in the operation of the block upon the stud to impart the oscillating movement of the yoke.

While specially adapted for the engine of our patent, as before mentioned, the invention is applicable to other engines in which oscillatory movement of thepiston is required.

The invention is also applicable to other machines in which a like reciprocating block is arranged to work in a groove or slot for the purpose of converting reciprocating into rotative motion, or vieeversa. We therefore do not wish to be understood as specifically limiting the invention to use in a steam-engme.

We make no claim in this application to the construction of the crank-block or to the yielding character of the yoke, also illustrated in the drawings, these features constituting the subject of an independent application filed of even date herewith, Serial No. 367,17 4.

\Ve claim- 1. In a steam-engine substantially such as described, and in which the pistons have a reciprocating movement imparted to them and also an oscillatory movement, ayoke attached to the pistons, and so as to reciprocate therewith, the plane of the yoke being at right angles to the plane of reciprocation, combined with a crank-pin block arranged to slide in said yoke in a plane at right angles to said path of reciprocation, the face of the said yoke constructed with a cam-shaped groove, and the crank-block provided with a stud adapted to work in the said groove, a block in said groove and around said stud, the said block consisting of two parts, the one part constructed with a seat upon one side of said stud and the other part with an elastic seat upon the opposite side of said stud, the said two parts adapted to yieldingl'y bear against the respective sides of said groove under the force of the said elastic seat upon the said stud, substantially as described.

2. In a yoke constructed with a cam-shaped slot or groove and having a stud arranged to reciprocate in said groove, whereby the reciprocating movement of one part is converted into rotative movement of the other part, or vice versa, the combination therewith of a block in said groove and around said stud, the said block consisting of two parts, the one part constructed with a seat upon one side of said stud and the other part with an elastic. seat upon the other side of said stud, the said two parts adapted to yieldingly bear against the respective sides of said groove under the force of the said elastic seat upon the said stud, substantially as described.

In testimony whereof we. have signed this specification in the presence of two subscribing witnesses.

FREDERICK II. LAFORGE. IIUGII .I. BARKER.

Witnesses:

J. B. THAYER, Jr. EDGAR DUDLEY FARIEs. 

